Biological safety is a paramount concern in modern society. Testing for biological contamination in foods or other materials has become an important and often mandatory requirement for developers and distributors of food products. Biological testing is also used to identify bacteria or other agents in laboratory samples such as blood samples taken from medical patients, laboratory samples developed for experimental purposes, and other types of biological samples. Various techniques and devices can be utilized to improve biological testing and to streamline and standardize the biological testing process.
A wide variety of culture devices have been developed. As one example, culture devices have been developed by 3M Company (hereafter “3M”) of St. Paul, Minn. In particular, culture devices are sold by 3M under the trade name PETRIFILM plates. Culture devices can be utilized to facilitate the rapid growth and detection of microorganisms commonly associated with food contamination, including, for example, aerobic bacteria, E. coli, coliform, enterobacteria, yeast, mold, Staphylococcus aureus, Listeria, Campylobacter, and the like. The use of PETRIFILM plates, or other growth media, can simplify bacterial testing of food samples.
Culture devices can be used to enumerate or identify the presence of bacteria so that corrective measures can be performed (in the case of food testing) or proper diagnosis can be made (in the case of medical use). In other applications, culture devices may be used to rapidly grow microorganisms in laboratory samples, e.g., for experimental purposes.
Biological scanning units refer to devices used to scan and/or count microbial colonies. For example, a food sample or laboratory sample can be placed on a culture device, and then the plate can be inserted into an incubation chamber. After incubation, the culture device can be placed into the biological scanning unit for automated detection and enumeration of bacterial growth. In this manner, biological scanning units automate the detection and enumeration of microbial colonies in a culture device, and thereby improve the biological testing process by reducing human error.